On Tue, Jun 2, 2020 at 5:13 AM Panu Matilainen <pmatilai@redhat.com> wrote:

Well, it's a guess.

Just tested the particular case of boost-devel install with plain rpm on
all of sqlite, bdb and ndb, and of the three, bdb is the slowest one.
The tested, expected behavior of sqlite is as fast or faster than bdb,
but of course it's *possible* previously unknown worst-case behaviors exist.

Lets start with the basics:
- is sqlite even involved - it will only be used on rawhide builds if
mock bootstrap is used
- does it make a difference if you override _db_backend to bdb/sqlite
from mock config / cli define
- a reproducer please (eg, what package is considerably slower to build
than before, and by how much)


boost-devel, nosync=True, bootstrap=False
real 0m6.083s
user 0m4.232s
sys 0m1.155s

real 0m6.134s
user 0m4.356s
sys 0m1.115s
---

boost-devel, nosync=True, bootstrap=True
real 0m7.464s
user 0m4.849s
sys 0m1.364s

I think this one was only slower because it converted the database? I saw a bunch of messages about looking for sqlite but finding bdb database.

real 0m7.234s
user 0m4.984s
sys 0m1.321s

Nope, about the same on a second run.
---

boost-devel, nosync=False, bootstrap=False
real 0m7.017s
user 0m4.388s
sys 0m1.144s
---

boost-devel, nosync=False, bootstrap=True
real 1m13.294s
user 0m6.723s
sys 0m2.761s
---

So it looks like boostrap=True and nosync=False is the culprit, which I inadvertantly got myself into. I did have either set and of course nosync would be False by default and it looks like bootstrap=True by default for rawhide.

I guess the next question is, why is that an order of magnitude worse of a combination?

Thanks,
Richard